1. Field of the Invention
This invention relates to the field of lock decoding, and more particularly to an apparatus and method for decoding cylinder type locks by determining the profile of a key, without first unlocking the lock, or otherwise destroying or opening the lock.
2. Brief Description of the Prior Art
Locks using key operated systems are widely available and known. Key locking systems, for example, are used in automobiles, homes, offices and industrial buildings, cabinets and other applications and locations requiring limited or restricted access thereto. Often, keys are used to lock important or critical items, such as the aforementioned vehicles, homes, etc. In many instances, keys, which must be carried separately from the lock with which they are to be associated and used, are prone to becoming misplaced, lost and even stolen. A key which is not readily available for use, such as a lost or misplaced key, creates complications for the lock user. While many individuals will have a duplicate or spare key, it sometimes will not be in their possession or readily available. In other instances, there may be no spare keys. Most commonly, among those keys which are misplaced are included automobile keys, and house keys. In the case of automobile keys, for example, it is often not enough to simply have a locksmith open a car door, since one will need to start the car engine in order for the vehicle to be used. To do this a key must be made. For example, where people have lost keys on vacation, in the ocean or some other place where it is not likely to be recovered, not only must the individual be given access to his or her vehicle, but also, the person must have a key in order to start the vehicle. While many manufacturers provide a key code which enables the mailing of a duplicate key which will fit that specific vehicle, usually the automobile dealers, and not locksmiths, are the only ones with access to the codes and equipment required to make a key which will fit. While a locksmith can obtain access to the automobile, for example, by picking a door lock, generally, this provides little help to the vehicle owner or user who then wishes to drive the vehicle to another location.
While mention was made of certain key codes, car dealers are not open twenty-four hours a day, and sometimes are not close by, rendering it impossible to have a new key made. Today, there are more difficulties encountered by the use of high security vehicle locks. These keys are even more difficult to duplicate and require specialized equipment for their production. High security type keys often include two profiles, one on one side of the key, and another on the opposite side of the key. The profiles are often separated by a wall between them.
In many cases, the only way to make a new key, when one has been lost, is to read the lock. This requires that the lock be disassembled in order to ascertain the proper profile of the key which will fit the lock and open it. This is often an expensive and impractical procedure, since the lock must be removed from its mounting and disassembled. In the case of an automobile, the lock must be removed from the door panel. This is considerably expensive and time consuming. Other difficulties, apart from removal of the lock, include encountering locks which cannot be readily disassembled, but must be destroyed and replaced. Thus if the lock must be destroyed, it will often be useless, except in the case of automobiles, for example, the key is still needed to operate the engine.
Among the many lock types are cylinder locks, which themselves, comprise many varieties. Cylinder locks, for example, can include pin tumblers and wafer tumblers which must be placed into proper positions by a key which is inserted into the keyhole of the cylinder of the lock. When the tumblers are set by the key into their proper positions, the key can then be turned to therefore rotate the cylinder of the lock relative to the outer housing or casing. Generally, the proper key is needed to move each tumbler into a position where it does not interrupt the rotation of the lock cylinder. For example, insertion of the proper key, that is, one having the correct profile, causes the pin or wafer tumblers to move into a position in which each tumbler is located within a zone defined generally by the outer surface of the cylinder of the lock. When the profile of the key is not correct, then one or more of the tumblers will extend from the inner cylinder into a groove or retaining feature generally located in the surrounding casing or outer housing to prevent relative rotation of the cylinder, and thereby prevent unlocking of the lock.
In a wafer type cylinder lock, often the wafers are interchangeably provided so that the lock can be made to use a different key by resetting the position, number and type of wafers used. Generally, each wafer is cut to one of several sets of dimensions corresponding to a notch of a particular depth, to be located at a point along the shank of a key for such a lock which corresponds with the position in which that particular wafer tumbler is located within the cylinder of the lock. For example, any two or more different wafers might be in any particular wafer position of the cylinder. In order to decode the lock to ascertain the key profile, the positions of each wafer within the cylinder must be ascertained.
In the past, methods have been proposed for decoding locks without the need for disassembly or destruction of the lock. One method includes the use of a visual aid for inspecting the interior of the lock to observe the positions of the individual wafers or tumblers. For example, U.S. No. Pat. 3,087,050 discloses the use of a lamp and probe for holding some of the tumbler wafers out of the way of the line of sight in order to permit observation of other wafer positions. This method requires the accurate estimation of the tumbler positions within the lock based on the observer's visual inspection. Because of small variations in the locations of the tumbler positions, and because of reflections and shadows of light, ascertaining the correct key profile by this method can prove difficult.
Another example is a side bar lock mechanism of the wafer type, disclosed in U.S. Pat. No. 4,185,482, issued to William B. Nail, the complete disclosure of which is herein incorporated by reference. The '482 patent discloses a tool which allegedly can be used for determining the bitings or cuts of a key that will open side bar locks employing wafer type tumblers. The lock mechanism disclosed in the '494 patent shows 5 wafer type tumblers, while there may be six tumblers with spacing along a longitudinal axis of the lock mechanism, for example, in General Motors type vehicle locks. While professional locksmiths can have information on the type of lock and types and numbers of tumblers used, the position of each tumbler within the lock for opening is not readily available to locksmiths. The locksmith must have the identification number of the lock. This is often difficult to obtain, since many times, automobile dealers will not maintain records of after a certain period of time, or cars might be sold to different owners. Moreover, even though the lock identification number may be present on the casing of the lock mechanism, this requires removal of casings, and even the steering wheel in order to gain access. Furthermore, in the case where an individual has locked his or herself out of a vehicle, gaining access thereto, itself, might prove to be a difficult obstacle.
Prior approaches to open a side bar type lock, where a key has been lost, include drilling the lock cylinder so that a pin or wire can be inserted into the lock in a position to exert considerable radially inward pressure on the side bar. This causes the leading edge of the side bar to bear against the tumblers with more pressure than normal, so that when a locksmith manipulates each tumbler with a pick, it is easier to align the V-notches in the tumblers with the side bar so that the lock can be opened. Of course, the problem with this approach is that the lock is ruined by the drilling and must therefore be replaced. If, for example, the lock is that of an automobile door, then the time and expense to replace the lock can be considerable because the inside door paneling, the handles, and controls must be removed to gain access to the interior.
Another decoding device and method for decoding cylinder locks is disclosed in U.S. Pat. No. 4,680,870, the complete disclosure of which is herein incorporated by reference. This device incorporates a slide which requires the user to then take readings from the slide in order to determine the key profile.
A need exists for an inexpensive method of decoding a lock without the need to disassemble or break apart, or otherwise damage the lock mechanism. Such a method and device would save time and expenses and permit a lock key to be readily duplicated when needed.